<!DOCTYPE html>
<html>
 <head>
  <title> 事件</title>   
 
 </head> 
 <body>
   <input type='text' id='txt1' /> 
   <select id='select'>
		<option value='+'>+</option>
		<option value="-">-</option>
		<option value="*">*</option>
		<option value="/">/</option>
   </select>
   <input type='text' id='txt2' /> 
   <input type='button' value=' = ' onclick="count()" /> <!--通过 = 按钮来调用创建的函数，得到结果--> 
   <input type='text' id='fruit' />   

   <script type="text/javascript" src="compute.js"></script>
 </body>
 
</html>